How fast does sewer water flow

As this occurs, it becomes time to plan for and construct expanded facilities, such that the permitted capacity remains larger than the actual flow being treated. Some content on this site is saved in an alternative format. Scroll for More Quick Links. One question that is frequently asked by individuals reviewing domestic wastewater treatment facility data is: What is the difference between capacity and flow? This short article provides guidance on the significance and use of these terms.

Summary Flow is the actual amount of water being treated, moved or reused. Flow frequently is expressed in MGD. Capacity represents the ability to treat, move or reuse water. Typically, capacity is expressed in MGD. Normally, the flow will be less than the capacity. It is then transported through the Inter-Island Tunnel to the pelletizing plant in Quincy, where it is dewatered, heat-dried and converted to a pellet fertilizer for use in agriculture, forestry and land reclamation.

If excessive levels of toxic chemicals are allowed to enter the system, they could either prevent the safe application of sludge as fertilizer or threaten the marine environment if discharged to ocean waters.

New regulations have been written by the MWRA to control the amount of toxic chemicals that companies can discharge into the sewer system. The MWRA's Toxic Reduction and Control Department is responsible for monitoring and enforcing the regulations and imposes fines against industrial polluters.

The MWRA also works with industries to encourage reductions in the use of toxic chemicals that might be discharged into the sewer system. Households are also an important source of toxic chemicals due to the careless dumping of toxic products down household drains. Used motor oil, pesticides, paints, solvents and even many household cleaners pose significant hazards to the environment. For most household jobs, less toxic alternatives are available.

About MWRA. Waste Water - Flow Capacity In sewage piping and pumping systems the fluid flow rate must be kept within certain limits to avoid operating problems Sponsored Links. Privacy We don't collect information from our users. Citation This page can be cited as Engineering ToolBox, Waste Water - Flow Capacity. Modify access date. The tank looks something like this in cross-section: In this picture, you can see three layers.

Wastewater comes into the septic tank from the sewer pipes in the house, as shown here: A septic tank naturally produces gases caused by bacteria breaking down the organic material in the wastewater , and these gases don't smell good. The following diagram shows an overhead view of a house, septic tank, distribution box and drain field: A typical drain field pipe is 4 inches 10 centimeters in diameter and is buried in a trench that is 4 to 6 feet about 1. The gravel fills the bottom 2 to 3 feet of the trench and dirt covers the gravel, like this: The water is slowly absorbed and filtered by the ground in the drain field.

Urban Wastewater Systems In urban and suburban areas where people are packed closer together and where there is a lot more wastewater to treat, the community will construct a sewer system that collects wastewater and takes it to a wastewater treatment facility. Here's what each stage does: The first stage, known as primary treatment , does the same thing a septic tank does. It allows the solids to settle out of the water and the scum to rise. The system then collects the solids for disposal either in a landfill or an incinerator.

The second stage, known as secondary treatment , removes organic materials and nutrients. This is done with the help of bacteria -- the water flows to large, aerated tanks where bacteria consume everything they can.

Typically, the third stage will use chemicals to remove phosphorous and nitrogen from the water, but may also include filter beds and other types of treatment. Chlorine added to the water kills any remaining bacteria, and the water is discharged. Measuring the Effectiveness of a Treatment Plant The effectiveness of wastewater treatment plants is measured on several different scales.

Here are some of the most common: pH - This is the measure of the water's acidity once it leaves the plant. Ideally, the water's pH would match the pH of the river or lake that receives the plant's output. BOD bio-chemical oxygen demand - BOD is a measure of how much oxygen in the water will be required to finish digesting the organic material left in the effluent. Ideally, the BOD would be zero.

Dissolved oxygen - This is the amount of oxygen in the water as it leaves the plant. If the water contains no oxygen, it will kill any aquatic life that comes into contact with it. Dissolved oxygen should be as high as possible and needs to cover the BOD.

Suspended solids - This is the measure of the solids remaining in the water after treatment. Ideally, suspended solids would be zero. Total phosphorous and nitrogen - This is the measure of the nutrients remaining in the water.

Chlorine - The chlorine used to kill harmful bacteria needs to be removed so it does not kill beneficial bacteria in the environment. Ideally, chlorine should not be detectable. Coliform bacteria count - This is the measure of fecal bacteria remaining in the water. Ideally, this number would be zero. Note that water in the environment is not totally free of fecal bacteria -- birds and other wildlife do introduce some.